This invention relates to a hydraulic device, such as a brake hydraulic pressure control device, including a solenoid valve mounted to a housing for opening and closing oil passages and adjusting the degree of opening of its valve portion, and particularly a hydraulic device in which the solenoid valve is mounted to the housing in an improved manner so as to simplify the structure of the solenoid valve and reduce the cost of the hydraulic device.
Conventional solenoid valves used in vehicle brake hydraulic pressure control devices are disclosed n JP Patent Publications 09-14500A (Patent document 1) and 10-82478A (Patent document 2).
The solenoid valve shown in Patent document 1 comprises a plunger for driving a valve body, a shaft (valve rod) integral with the plunger, a core as a guide member through which the shaft is inserted, and a sleeve made by pressing and covering the plunger and the core. The solenoid valve is mounted to the housing by fixing the sleeve to the housing.
The housing has a mounting hole in which the valve portion of the solenoid valve is mounted. The mounting hole has a shoulder which divides the mounting hole into a large-diameter portion including the open end of the mounting hole and the remaining small-diameter portion. The core of the solenoid valve has on its outer periphery a tapered portion (flange) having a tapered top surface which is inclined radially outwardly and downwardly. The sleeve of the solenoid valve has a tapered skirt portion at its bottom open end. The sleeve is fixed to the housing by seating the tapered portion of the core on the shoulder of the mounting hole of the housing, placing the tapered skirt portion of the sleeve on the tapered top surface of the tapered portion of the core, fitting a back-up ring which can be fitted in the large-diameter portion of the mounting hole on the sleeve to place the ring on its skirt portion, and caulking the portion of the housing near the open end of the mounting hole to press the tapered portion of the core through the back-up ring.
The oil passages in the housing are liquid-tightly sealed at the portion where the solenoid valve is mounted by forming a metal-sealed portion by pressing the tapered portion of the core against the shoulder of the mounting hole.
In Patent document 2, an annular spacer is used instead of the back-up ring. The solenoid valve of Patent document 2 is fixed to the housing by plastically deforming the annular spacer to press it into an undercut portion formed on the inner periphery of the mounting hole.
In the arrangement of Patent document 2, (instead of the tapered portion of the Patent document 1) a large-diameter portion having no tapered top surface is formed on outer periphery of the core and seated on the shoulder of the mounting hole. The sleeve has a flange at its open end portion. With the flange of the sleeve placed on the large-diameter portion of the core, the flange of the sleeve and the large-diameter portion of the core are pressed by the annular spacer and are pushed into the undercut portion and fixed in position in the mounting hole by plastically deforming the annular spacer. The oil passages in the housing are liquid-tightly sealed at the portion where the solenoid valve is mounted in the same manner as with the solenoid valve of Patent document 1.
With the solenoid valves of Patent documents 1 and 2, when the sleeve is fixed in position by the back-up ring or annular spacer, the sleeve is compressed. In order for the sleeve to be able to withstand the compression force and in order to keep sufficiently close contact between the liquid-tight seal surfaces, the sleeve, which is formed by pressing, is reinforced by the core. Thus, high rigidity is required for the core.
With the solenoid valves of Patent documents 1 and 2, the core, which is made of a magnetic material and is magnetized when the coil is energized, is provided between the plunger and the housing. But there are solenoid valves of a different type in which the plunger is located between the housing and the magnetic core. In such solenoid valves, no magnetic core is necessary between the plunger and the housing. But in such a case too, it is necessary to provide a core having high rigidity between the plunger and the housing in order to reinforce the sleeve. This complicates the structure of the solenoid valve and also increases its cost.
Thus, for the type of solenoid valves in which the plunger is provided between the magnetic core and the housing, it is being desired to improve the connecting structure of the sleeve, which is formed by pressing, to the housing to simplify the structure of the solenoid valve.